In his excellent book, The Master Switch, Tim Wu laid out a history of radio in the US that started with amateurs and techies experimenting with a new technology and finding ways to connect to each other with it. The story ended with radio as we know it today: a broadcast medium with its use as a more social communication tool relegated to ham radio enthusiasts. It's tough to know if Twitter will ultimately come to the same extreme end as radio has, but as I listened to Twitter CEO Dick Costolo's conversation with Peter Kafka of All Things D at tonight's D: Dive into Media conference, I started to believe that Twitter could be in the early stages of the same trajectory.

The two began with the issue of the day: the recent dust up over Google's "Search Plus Your World" issue — which has Google is foregrounding its own Google+ social results and has Twitter, Facebook and others point out that Google's own algorithms indicate that there are more relevant results on other networks. Costolo pointed out that Google has indexed something on the order of three billion Twitter pages, so it certainly is aware of what's happening there. Moving on to the fact that Google pulled live Twitter live results from its search pages, Costolo says that that particular breakdown was not just about money, but that they could not work out "the details."

In both cases, Costolo displayed a cool and easygoing attitude towards Google and its actions, expressing disappointment but not necessarily deep concern. Disappearing from the front page of Google's search results and seeing your own more-relevant pages get buried under Google+ results would strike a combination of fear and red-hot rage in your average internet startup CEO, but Costolo is not that CEO. If you read between the lines of his comments this evening, he sees Twitter moving on to a large enough stage where even Google (or Facebook) couldn't take it down: "It's not a zero sum game."

Costolo doesn't seem to believe that Twitter needs to fight directly with Google+ or Facebook, and I think it's because he's trying to play a different game. He pointed out that over 40 percent of active Twitter users straight-up don't tweet. They don't write tweets, hit the re-tweet button, or otherwise engage with Twitter at all — except to read it. They're active users only insofar as they visit the site on a regular basis, but for them Twitter isn't a social network at all, it's simply another source of information on the internet. You'd think that would be terrible Twitter, but Costolo has this opinion of the stat: "That's fantastic."

While Twitter may have gotten its initial growth from conversations, what it is increasingly about is broadcasting. Costolo was at the ready with several examples were rooted not in the everyday sharing between friends but in the more traditional, big-media broadcasting model. He talked about celebrities engaging directly with fans, companies acting as effective advertisers on Twitter, and even dark portents for presidential candidates who don't use Twitter, "I really think 2012 is going to be the Twitter election."

Kafka asked directly if Twitter was a "media company" and Costolo contends that it's not, as Twitter just distributes the content instead of creating it. That kind of attitude towards Twitter does make a bit of sense — connections between users are much more tenuous than they are on Facebook — but it also makes Twitter as a kind of next-generation broadcasting platform instead of a direct competitor to Google or Facebook. If Costolo has that conception of Twitter, it will have consequences for its users.

Twitter's goal, of course, is to sell advertising — the other business models that have been rumored for the company have largely fallen by the wayside. Costolo says that the company can survive based simply on the types of advertising it currently offers, needing only to "ramp it up." Twitter's new advertising push (no comment, by the way, on expanding brand pages) requires that the company broadcast to millions (or billions) of people in a targeted and relevant way. In that sense the kinds of conversations that happen with @replies and Direct Messages are valuable to the company only insofar as they can allow Twitter to better target advertising to you. The recent redesign of the Twitter web pages and its official Twitter apps that shuffled Direct Messages off to a corner is essentially a side effect of this basic attitude: Twitter isn't a messaging company, it's a broadcasting (social) network.

To give another example, Twitter didn't shut down in protest of SOPA or PIPA, though not because of a lack of opposition to them as they existed. Instead, Costolo was happy to have Twitter be the medium of conversation about other sites shutting down and also the medium of protest against congress: "You don't pull the batteries out of the microphone." Still, Twitter finds itself in a strange situation: it's often a source of piracy and wants to partner closely with the same media companies that were pushing for SOPA and PIPA. So those who were hoping Twitter would be a crusader for anything that might look like SOPA in the future are in for a disappointment, as Costolo says that "there is probably a middle ground."

Twitter's new role pretty much necessitates that more nuanced (or "hedged," depending on your inclinations toward the legislation) position on SOPA. It's no longer your standard, familiar internet startup — but it's also not yet turned into what it will "grow up" to be. Costolo's comments and Twitter's redesign both point toward something less intimate and more crowded than a social network, but nevertheless more crowdsourced and more human than a broadcast network. There's likely a space where Twitter can survive in between those two extremes, and Costolo will need to find it soon. The impending, virtually inevitable IPO (on which Costolo naturally has no comment) will mean that there are more stockholders demanding a stable business model — and somehow I think that Twitter is aiming higher than being a 21st century ham radio.